Home / Cognitive impairment in Parkinson’s

Cognitive impairment in Parkinson’s

Cognitive impairment in Parkinson’s

Cognitive impairment (CI) is among the most common non motor symptoms of Parkinson’s disease (PD). The neurodegenerative disease causes drastic changes to the structure and chemistry of the brain which in turn can affect the patient’s cognition, behaviour, mental health, general well-being, etc.

With a Parkinson’s diagnosis, most treatments focus on its motor symptoms. However, recent studies have shown just how severe and life-altering the non-motor symptoms of PD can be too. Some patients experience CI in a mild form, also known as mild cognitive impairment (MCI), while some may experience subjective cognitive decline (SCD). The third kind of impairment is dementia. The degree of impairment and its accompanying symptoms may differ from patient to patient, depending on which stage of PD they are at.

Plexus Parkinson’s Disease Rehabilitation Program offers the best treatment for Parkinson’s. It is designed as a holistic rehabilitation program that restores motor function, mitigates non-motor ailments, and improves the overall quality of life of the patient.

What is Parkinson’s?

Parkinson’s is a chronic and degenerative brain disorder that impairs muscle control, balance, and movement. PD causes the cells in substantia nigra (in the basal ganglia) to deteriorate, thereby inhibiting the brain’s ability to produce dopamine. As the disease progresses, the neurons in the brain completely deteriorate, causing severe motor impairment, tremor, stiffness, slowed or delayed movement, dysphagia, sleep issues, fatigue, difficulty in speech, and so on.

Parkinson’s induced cognitive impairment

Parkinson’s cognitive impairment has a varying range that is characterised based on the extent of damage to the central nervous system (particularly the brain), the stage of PD, and the symptoms experienced by the patient.

There are three types of cognitive impairment in patients with PD. They are:

  • Subjective cognitive decline: a perceived decline in cognitive abilities
  • Mild cognitive impairment: a gradual decline in cognitive abilities; this kind of impairment can follow the trajectory of PD and may even decline further as the disease advances
  • Parkinson’s disease dementia: significant cognitive decline that affects memory, reasoning, and thinking

Dementia brought on by PD is of two types. These can be distinguished by their symptoms.

  • Parkinson’s disease dementia (PDD) – the patient experiences a substantial decline in cognitive function particularly after a year or more of experiencing reduced motor function
  • Dementia with Lewy Bodies (DLB) – the patient can either experience cognitive decline right in the initial stages of PD; or along with a decline in motor function (both will progress together)

The combined disability of reduced motor function and cognitive impairment can be devastating for the patient. It can also have a very significant impact on the caregiver and their relationship with the patient. Severe cognitive impairment in PD is most commonly associated with:

  • Cost of treatment
  • Diminished quality of life
  • Caregiver burden and distress
  • Increased mortality
  • Poorer treatment outcomes
  • Deteriorating daily function

Causes  of cognitive impairment in PD

With PD inhibiting the brain’s ability to secrete dopamine, the drop in the level of the neurotransmitter is touted as one of the main causes for cognitive impairment in patients. The impairment that results from a drop in dopamine level is usually classified as mild and restricted.

Besides this, the alterations made to the brain’s structure is also regarded as a contributing factor to cognitive impairment. Medical researchers are in the process of trying to ascertain the changes in two other chemical messengers – norepinephrine and acetylcholine – as additional (probable) causes of memory issues and executive function loss in patients.

Effects of cognitive impairment

The onset of Parkinson’s induced cognitive impairment may be limited to one or two mental areas, with its severity differing from person to person. These areas include:


  • Tasks that require them to maintain or shift their attention may be challenging
  • Trouble with mental calculations (especially while performing a task)

Executive function:

  • Inability to multitask
  • Difficulty in planning and completing tasks

Speed of mental processing:

  • Delayed response to verbal or behavioural stimuli
  • Taking longer to complete a task
  • Taking time to retrieve information from memory


  • Trouble finding the right word
  • Loss of language/speech when under pressure or stress
  • Slurred or unarticulated speech
  • Naming or misnaming objects
  • Difficulty in comprehension and grasping smaller details


  • Trouble organising and recalling information
  • Inability to perform everyday tasks like making coffee, doing laundry, etc.
  • Short-term and long-term memory impairment may accompany dementia

Visuospatial changes:

  • Difficulty in depth and distance perception
  • Visual misperceptions (illusions)
  • Inability to recognise faces, facial expressions, and tell them apart
  • Trouble understanding surrounding environment, especially changes made to routine

Diagnosing cognitive impairment

Typically, a neurologist will interview the patient and will ask their family/caregivers to share their concerns/observations. The neurologist will make an assessment based on the patient’s understanding of who and where they are, the date and year, memory, language, attention span, and problem-solving skills.

After this, the neurologist is likely to refer the patient to an Occupational Therapist for a detailed assessment. Since some of the symptoms of Parkinson’s induced cognitive impairment appear to be the same as impairment induced by Alzheimer’s disease, stroke, or dementia, a correct assessment is absolutely vital. 

Other symptoms non-motor symptoms of PD that can affect cognition

Depression, sleep issues, anxiety, fatigue can also affect cognition.


A combination of medications and behavioural strategies may be prescribed by the doctor and therapist is regarded as the best treatment for cognitive impairment. The behavioural strategies include two kinds of therapy, which are:

  • Behavioural management – changes in the patient’s environment are made so as to reduce perceptual and memory challenges
  • Cognitive rehabilitation  therapy – ideal for patients with mild cognitive impairment; the therapy focuses on teaching alternative ways to make up for memory and thinking problems

How can caregivers help?

Cognitive impairment can be extremely embarrassing to the patient. Imagine not knowing how to make your favourite cup of coffee, something which you’ve been doing every day for the last so many years. Cognitive impairment can significantly pull down a patient’s confidence and morale. As caregivers, we can support them by thinking from their point of view.

Here’s how you can help a loved one who is suffering from cognitive impairment:

  • Be respectful – for instance, do not be in a hurry to finish their sentences while they appear to be struggling for words (instead, you can provide them with helpful cues)
  • Ask if they’d like your help, if they say no, then respect that no
  • Put reminder notes and lists – make sure the language you use is gentle and affirming
  • Make eye contact when speaking to them to gain and hold their attention
  • Offer prompts to help with memory – for instance, you can ask Did Akshay call? instead of Did anyone call?
  • Stick to their routine as much as possible; in case of change in routine, try and prepare them mentally for the change in advance

Plexus Parkinson’s Disease Rehabilitation Program works towards mitigating the severity of non-motor and motor symptoms, as well as progression of PD. Our highly skilled and experienced team of neuropsychiatrists and occupational therapists work in tandem to devise the most ideal cognitive rehabilitation approach and behaviour therapy for you or your loved one. Cognitive impairment can be debilitating, but it doesn’t have to be disheartening. We can make things better and offer the patient an improved quality of life.  


Stem cell therapy for Parkinson’s

At Plexus Neuro and Stem Cell Research Center, we use autologous stem cells taken from the patient’s own body. As India’s leading stem cell specialists, we assure you of a safe treatment with absolutely no adverse effects.

 Stem cells are injected back into the patient’s body . These injected cells have the potential to develop into dopamine-secreting neurons thereby reducing the progression of Parkinson’s and giving the individual a fighting chance to not let the disease get the better of them.

 Book an appointment with us today.

Call +91 89048 42087 | 080-2546 0886

080-2547 0886 | 080-2549 0886


What are the common cognitive problems associated with PD?

Attention span, memory problems, deterioration of executive function, perception and visual challenges are some of the most common cognitive problems associated with PD.

Does PD cause mental confusion?

Yes, PD is known to cause memory troubles, confusion, disorientation, slowed thinking, and/or dementia.

Do all PD patients get dementia?

Not all PD patients get dementia, but a PD diagnosis does increase the risk of dementia.

At what stage of PD does dementia set in?

PD induced dementia is of two types:

  • Parkinson’s disease dementia (PDD) – the patient experiences a substantial decline in cognitive function particularly after a year or more of experiencing reduced motor function
  • Dementia with Lewy Bodies (DLB) – the patient can either experience cognitive decline right in the initial stages of PD; or along with a decline in motor function (both will progress together)

Does PD change personality?

Yes, the neurological changes to the brain caused by PD can alter the personality and behaviour of the individual.

WhatsApp chat
Click here to check your eligibility for treatment
Translate »